Solid fuel combustion in inefficient cooking stoves in poorly ventilated areas causes heavy maternal exposure to carbon monoxide (CO) and to fine particulate matter (PM2.5), both known to cause fetal anoxia. However, the evidence linking indoor smoke to and adverse pregnancy outcomes is limited and sometimes conflicting;and evidence linking indoor smoke to infant neurodevelopment is nonexistent. Many studies use indirect measures of smoke exposure and reported measures of health outcomes, and do not adequately account for confounding and interactions. The WHO recommends that additional, high quality studies are required to confirm the risk estimates, with an emphasis on accurate assessments of exposure and gestational age. In the proposed research, we plan to evaluate the relationship between solid fuel use and birth outcomes and infant neurodevelopment among a semi-urban population residing in Gampaha district, Sri Lanka. The aims are to measure the accuracy of questionnaire information on solid fuel use as a surrogate for measured levels of indoor PM2.5 and CO, and to evaluate the relationship between prenatal exposure to solid fuel smoke exposure and fetal growth (low birth weight, head circumference and length) and between solid fuel smoke and neurodevelopment at birth. We will measure PM2.5 and CO by real-time continuous monitoring and assess gestational age by ultrasound. This Indo-US collaboration will add to the body of knowledge on solid fuel use as a risk factor for birth outcome and infant neurodevelopment and serve as a first step for development of community-based interventions to lower associated disease burden. PUBLIC HEALTH RELEVANCE: Indoor air pollution from combustion of solid fuels for cooking has been identified as one of the ten most important risk factors in global burden of disease. This study will add to the body of knowledge on solid fuel use as a risk factor for birth outcome and infant neurodevelopment, and benefit from a well-established Indo- US collaboration among investigators with diverse and supplementary backgrounds while at the same time fostering technology transfer between the two partner institutions.